You can replace the rating plug (chip) but you need to install the correct one.
The correct rating plug would be TR8B400.
Dissecting the part number helps to understand this. The 8 represents the rating of the circuit breaker current transformers, in this case 800 amps. The 400 represents the continuous current rating of the circuit breaker.
Another option, as pointed out by DPC, is to reduce the long time pickup setting to 0.5x. The pickup setting is a multiplier that is applied to the continuous current rating. In this case, 800 x 0.5 = 400 amps.
For setting the instantaneous pickup, keep in mind that this is also a multiplier of the continuous current rating. Thus, for a 2400 amp instantaneous trip (6x of motor current) the setting would be 3x. This is because 800 x 3 = 2400.